The dead mariner was still seated at the desk by the radio in the 12-metre (40ft) yacht, slumped over on his right arm, when the fishermen found him. Investigators believe he died of a heart attack or stroke and was swiftly preserved in the warm, salty ocean air.

Police identified Bajorat, an experienced sailor, from photographs, letters and other documents strewn around the yacht’s cabin. The vessel, which had a broken mast and was partly filled with water, was towed into Barobo for a formal investigation.

The mummified body of Manfred Fritz Bajorat, which was found slumped at a table in his yacht ‘like he was sleeping’. Photograph: Barobo police

Inspector Mark Navales, deputy police chief in Barobo town, said that while the cause of Bajorat’s death was unclear, there were no signs of foul play

The weather conditions would have rapidly dried the dead body from the outside, turning the skin into a leathery protective barrier against bacteria and insects. But under the fat and muscle, bacteria in the gut may have begun to decompose the body from the inside.

“The air, heat, and saltiness of sea are all very conducive to mummification,” said Peter Vanezis, professor of forensic pathology at Barts and the London School of Medicine and Dentistry.

“It starts within two to three weeks. The fingers and other extremities – the nose, the face – dry quickly, and in a month or two they are well gone.”

A week after death, the skin could become yellow, hard and leathery, with complete mummification occurring after several weeks, Frank Wehner, a forensic pathologist at Tübingen University, told the Bild newspaper. The light coating of grey that covers the mummified body is believed to be mould.

While Bajorat has been named through items on the yacht, investigators may yet restore his facial features and obtain fingerprints to confirm his identity.

Vanezis performed the same exercise on the mummified corpse of a man discovered in the funnel of a ship that arrived at Tilbury port from Mombasa in Kenya.

He used dilute sodium hydroxide – caustic soda – to soften up the mummy’s hardened skin. “As a result, we got back his facial features and managed to get fingerprints off his fingers too,” Vanezis said.

Among the material found on the yacht was a letter from Bajorat to his former wife, Claudia, who died in 2010, reports claim.

According to the Mirror, the note read: “Thirty years we’ve been together on the same path. Then the power of the demons was stronger than the will to live. You’re gone. May your soul find its peace. Your Manfred.”